Cold spray deposition using Titanium powder was carried out to investigate the effects of powder morphology and powder preheating on the coating properties such as porosity and hardness. The in-flight particle velocity of Ti powder in cold spray process was directly measured using the PIV (particle image velocimetry) equipment. Two types of powders (spherical and irregular ones) were used to manufacture cold sprayed coating layer. The results showed that the irregular morphology particle appeared higher in-flight particle velocity than that of the spherical one under the same process condition. The coating layer using irregular morphology powder represented lower porosity level and higher hardness. Two different preheating conditions (no preheating and preheating at ) were used in the process of cold spraying. The porosity decreased and the hardness increased by conducting preheating at . It was found that the coating properties using different preheating conditions were dependent not on the particle velocity but on the deformation temperature of particle. The deposition mechanism of particles in cold spray process was also discussed based on the experimental results of in flight-particle velocity.

As a part of investigation to use sardine(Sardinops melanoslicta) more effectively as a food source, this study was undertaken the processing condition of rapid- and low salt-fermented liquefaction of sardine. To prepare rapid fermented products, the chopped whole sardine was added 8% NaCl and then preheating treatment at 40℃, 45℃ and 50℃ in the manufactured fermenter(180L) for 9 hrs, and then fermentation at 33℃ for 90 days. The chemical changes such as amino nitrogen(amino-N), volatile basic nitrogen(VBN), and histamine in the hydrolysates of fermented sardine were analyzed as well as viable cell count and organoleptic evaluation during fermentation to compare the quality between control and preheating samples. During fermenting, the amino-N in the hydrolysates increased rapidly during the first 30 days and slowly thereafter. The highest content of amino-N appeared at 75 days in control sample and 60~75 days in preheating samples. The changes of VBN in the hydrolysates increased rapidly during first 15 days in control samples and 30 days in preheating samples. However they were generally low level in preheating samples. Histamine content in the hydrolysates of the control samples increased markedly after 15 days, but preheating samples were generally low level, and then 75~90 days of fermentation reached to the maximum which was about 2.0~3.0 times lower than that of control samples. As for the organoleptic flavor evaluation, the control and preheating at 40℃ samples were unpleasant odor after 15 and 60 days, respectively. But preheating at 45˚ and 50˚ samples were fresh odor after 90 days fermentation.

In order to establish the processing condition of salt-fermented liquefaction of sardine (Sardinops melanoslicta), effect of temperature, pH value, and concentration of salinity on crude enzyme activity of sardine viscera were investigated. The optimum temperature range of crude enzyme activity in sardine viscera was 45~50℃ and the optimum pH value of it was 9.8. According to the concentration of salinity increased the crude enzyme activity in sardine viscera decreased. The relationship between concentration of salinity (X) and the crude enzyme activity (Y) in sardine viscera is shown as follows; Y=-0.01363X+0.7676 (r=-0.88). For the purpose of processing conditions of rapid- and low salt-fermented liquefaction of sardine, changes of viable cell count, histamine content, and volatile basic nitrogen (VBN) in the chopped whole sardine with 8% NaCl during preheating process at 40˚, 45˚ and 50℃ for 48 hrs were analyzed. During preheating, initial viable cell counts of chopped whole sardine were 104-7/g, but they decreased 101-5/g after 48 hrs. Histamine contents during preheating process at 40˚ and 45℃ were gradually increased, whereas at 50℃ were almost the same level after 48 hrs. VBN contents were continuously increased during preheating, but preheating at 50℃ samples were lower level than that of 40˚ and 45℃ ones. For the purpose to accelerate the fermentation and liquefaction of chopped whole sardine, preheating at optimum temperature of crude enzyme activity for 48 hrs was useful processing method and the contents of viable cell count, histamine, and VBN were safety level for food sanitation.

A study was undertaken to determine the thermal inactivation of Escherzchia coli O157:H7 as influenced by the effects of temperature, time, suspension medium and ascorbate. Tryptic soy broth was more heat resistant than phosphate buffer (pH 7.1), with D values of 1.52-1.68 min at 60℃ and 1.51-1.63 min at 70℃ compared with 1.52-1.65 min at 60℃ and 1.26-1.61 min at 70℃ for phosphate buffer as suspension medium. E. coli O157:H7 was completely inhibited within 30 min when small inoculum (10^6 CFU/ml) was heated at 70. When E. coli O157:H7 was preheated at 48℃ for 60 min in phosphate buffer before heating, D values were 1.28-1.60 min at 60℃, and 1.13-1.56 min at 70℃, showing that preheating increases the heat resistance of the strain. Phosphate buffer containing ascorbate (0.001 M) was enhanced the thermal inactivation of the strain when inoculated as large inoculum (10^9 CFU/ml), while ascorbic acid was no effect at low cell concentrations (10^6 CFU/ml).

본 연구는 염장과정 중 무의 예열처리 및 chitosan의 첨가가 무의 조직감에 미치는 효과를 알아보기 위하여 압착시험, 침투관통시험 및 절단시험에 의해 조직감의 변화를 측정하고 펙틴질의 변화를 측정하였다. 또한 관능검사를 실시하고 무의 조직감에 대한 관능적 평가와 기계적 측정치와의 관련성을 조사하였다. 그 결과는 다음과 같다. 1. 비 열처리구에 있어서 chitosan 첨가군의 압착변형력은 대조군의 압착변형력에 비해 높은 것으로 나타났다. 열처리구에 있어서는 각 첨가군들의 압착변형력은 염장이 진행됨에 따라 감소하는 경향을 보였다. (p<0.05). 침투관통력은 대조군과 chitosan 첨가군에서 모두 감소하였으나 chitosan 첨가군이 보다 높은 침투관통력을 나타내었다(p<0.05). 절단력은 비 열처리구에서 염장이 시작되면서 증가하여 염장기간 내내 높은 절단력을 유지하였으며, 특히 chitosan 첨가군의 절단력은 염장과정 중 크게 증가하였다. 열처리구의 절단력은 대조군에서는 염장 초기에 급격히 증가한 추 염장4일째부터 크게 감소하였으나, chitosan 첨가군은 염장기간 내내 비슷한 수준을 유지하였다. 2. 대조군의 HWSP는 염장 2일째까지 감소하다가 증가하였으며 HXSP는 염장 2일째까지 증가하다가 이후 계속 감소하였으나 생무보다는 높은 함량을 나타내었다. HCISP는 염장과정 중 계속 감소하였다. 그러나 열처리에 의해서 HXSP는 감소하였다. 한편 chitosan 첨가군의 HWSP는 계속 감소하였으며 HXSP와 HCISP는 계속 증가하였는데 이때 HCISP의 증가가 더욱 뚜렷하였다. 또한 열처리구도 같은 경향을 나타내었다. (p<0.05). 3. 염장과정 중 비 열처리구의 단단한 정도와 아삭아삭한 정도는 감소하였으나 질긴 정도는 증가된 것으로 평가되었다. 그러나 열처리구의 질긴 정도는 감소하였으며 chitosan 첨가에 의하여 무의 단단한 정도는 증가하였다.(p<0.05). 한편, 압착변형력과 침투관통력은 무의 단단한 정도와 아삭아삭한 정도와 상관출계가 높았으며 절단력은 질긴 정도와 상관성이 다소 높게 나타났다(p<0.01). 이상의 결과로서 chitosan의 첨가는 비 열처리구와 열처리구에서 무의 조직감을 향상시킨 것으로 나타났다. 예열처리에 의한 효과는 담금 초기에 나타났으며 예열처리와 chitosan 첨가에 의한 병용 효과는 없는 것으로 나타났다.

Fresh-cut 멜론의 연화 억제를 위해 열처리를 행하였으며 그에 따른 저장 중 품질 특성과 texture를 조사하였다. 직접적인 열처리에 의한 과실의 품질 열하를 방지하기 위하여 전과(全果, whole fruit)를 저온(5)에서 열처리하고 저온(5)에서 24시간 저장한 후, 멜론 cylinder를 가공하였다. 저장중의 포장 내 가스 조성의 변화를 통한 호흡특성, 색도 변화, pH, 가용성 고형분 함량 등의 품질 특성 및 texture를 측정

수삼의 증삼전 열처리로 홍삼중의 추출가능 물질은 물추출물 뿐만 아니라 60%주정 수용액 추출물의 양을 근본적으로 다량 생성시켜 추출수율을 높였다. 또한 갈색도가 증진되었으며, 전분질을 함량을 저하시켜 추출물중 원심분리박의 대부분을 차지하고 있는 전분을 감소시키므로써 이의 제거를 위한 원심분리기 등 고가의 공정 단축이 가능할 수 있다. 증삼 전 예열 적정온도는 70℃에서 60분이 적합하였으며 증삼시간에 따라서는 엑스추출율의 차이가 크지 않았다. 예열 조건별 물 추출물 엑스의 향미 비교에서 향과 맛 모두 당의 특성 향미가 증진됨을 나타냈다.